Why do I get the feeling that the nerfs around every strong ADC is happening right before new ADC?

It occurred to me after reading about the Kog nerfs (which don't get me wrong they are warranted, I'm not disputing the nerf to his damage), that we are seeing a steady pattern here. Now riot announces "a super high-risk, high-reward marksman, in the vein of well… Vayne." (from the riot announcement) coming next. Why does this make me think that they are nerfing these other hyper carries to make way for the new pending king/queen of bot lane? I just have a very bad feeling about the timing of these changes. The only ADC I can think of being buffed lately is Jinx and it wasn't a gigantic buff her win rate is still only slightly better than it was.